Differential cell growth enables flexible organ bending in the presence of environmental signals such as light or gravity. A prominent example of the developmental processes based on differential cell growth is the formation of the apical hook that protects the fragile shoot apical meristem when it breaks through the soil during germination. Here, we combined in silico and in vivo approaches to identify a minimal mechanism producing auxin gradient-guided differential growth during the establishment of the apical hook in the model plant Arabidopsis thaliana. Computer simulation models based on experimental data demonstrate that asymmetric expression of the PIN-FORMED auxin efflux carrier at the concave (inner) versus convex (outer) side of the hook suffices to establish an auxin maximum in the epidermis at the concave side of the apical hook. Furthermore, we propose a mechanism that translates this maximum into differential growth, and thus curvature, of the apical hook. Through a combination of experimental and in silico computational approaches, we have identified the individual contributions of differential cell elongation and proliferation to defining the apical hook and reveal the role of auxin-ethylene crosstalk in balancing these two processes. © 2016 American Society of Plant Biologists. All rights reserved.
We thank Martine De Cock and Annick Bleys for help in preparing the manuscript, Daniel Van Damme for sharing material and stimulating discussion, and Rudiger Simon for support during revision of the manuscript. This work was supported by grants from the European Research Council (StartingIndependentResearchGrantERC-2007-Stg-207362-HCPO)and the Czech Science Foundation (GACR CZ.1.07/2.3.00/20.0043) to E.B. and Natural Sciences and Engineering Research Council of Canada Discovery Grant 2014-05325 to P.P. K.W. acknowledges funding from a Human Frontier Science Program Long-Term Fellowship (LT-000209-2014).
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Žádníková P, Wabnik KT, Abuzeineh A, et al. A model of differential growth guided apical hook formation in plants. Plant Cell. 2016;28(10):2464-2477. doi:10.1105/tpc.15.00569
Žádníková, P., Wabnik, K. T., Abuzeineh, A., Gallemí, M., Van Der Straeten, D., Smith, R., … Benková, E. (2016). A model of differential growth guided apical hook formation in plants. Plant Cell, 28(10), 2464–2477. https://doi.org/10.1105/tpc.15.00569
Žádníková, Petra, Krzysztof T Wabnik, Anas Abuzeineh, Marçal Gallemí, Dominique Van Der Straeten, Richard Smith, Dirk Inze, Jirí Friml, Przemysław Prusinkiewicz, and Eva Benková. “A Model of Differential Growth Guided Apical Hook Formation in Plants.” Plant Cell 28, no. 10 (2016): 2464–77. https://doi.org/10.1105/tpc.15.00569.
P. Žádníková et al., “A model of differential growth guided apical hook formation in plants,” Plant Cell, vol. 28, no. 10, pp. 2464–2477, 2016.
Žádníková P, Wabnik KT, Abuzeineh A, Gallemí M, Van Der Straeten D, Smith R, Inze D, Friml J, Prusinkiewicz P, Benková E. 2016. A model of differential growth guided apical hook formation in plants. Plant Cell. 28(10), 2464–2477.
Žádníková, Petra, et al. “A Model of Differential Growth Guided Apical Hook Formation in Plants.” Plant Cell, vol. 28, no. 10, American Society of Plant Biologists, 2016, pp. 2464–77, doi:10.1105/tpc.15.00569.
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